Heartland Earthworks Conservancy

16/03/2026

12/08/2025

One of the very important things HEC does is advocate for the identification and preservation of earthworks and mounds when they may be affected by government permitted actions, such as the approval of industrial scale solar farms by the Ohio Power Siting Board (OPSB) and the Public Utilities Commision of Ohio. Last evening I presented testimony before the OPSB on an archaeological investigation conducted by a private firm for a proposed 1,500-acre solar farm in Fairfield County. We have previously done so on other projects. The archaeological consulting firm that did the investigation failed to identify a mound and an earthwork they reported were in the project area based on background research. This failure was likely because they did not conduct their investigation using archaeological geophysics that may have found these and other important sites that undoubtedly are buried below the plow zone. Most archaeological investigations in Ohio are done without conducting geophysical surveys. This is not the way to practice good archaeology in the 21st century! Collecting artifacts from the ground surface and digging shovel test pits to the base of the plow zone every 50 feet or so are not efficacious methods for detecting important archaeological sites buried below the plow zone when sub-plow zone impacts will occur. Geophysical methods must be used. We will continue to advocate for best practices in archaeology.

08/06/2025

Some pics from our visit today to the Fortified Hill earthwork site near Hamilton, Ohio. Preservation efforts coming to fruition…nice :)

08/06/2025

Today we visited the Fortified Hill earthwork site in Hamilton, Ohio. You might recall several years back when we helped save the site during a public auction. Many thanks to the Harry T. Wilks Foundation for making the purchase and turning the site over to Pyramid Hill! Since then, a number of gung-ho volunteers and a few members of the Pyramid Hill staff have worked hard to get the site ready for visitors. While still a work in progress, Pyramid Hill is officially doing site tours now! Check out this link for more info:

Pyramid Hill is currently working on the Native Earthworks site of Fortified Hill as looks forward to the day when it can be opened to the public. Learn more about the site and stay up to date on an estimated opening

27/04/2025

A few days ago a friend and fellow earthwork enthusiast, Bob Neinast, sent over an 1877 description of an earthwork from Fairfield Co. Ohio described as “another embankment, enclosing some 10 or 12 acres.” A circle of 12 acres would be over 800 ft across—within the size range of a Great Circle. These are some of the largest standalone geometric earthworks in Ohio and the most famous is the Great Circle at Newark—it is over 1200 ft wide.

So, we all set about looking for evidence of this possible great circle. A search of old aerial photographs found it! Here we show 1938, 1951, and 1970 images. The outline of the earthwork, which is not quite a perfect circle, is shown in yellow on a modern aerial photo. A look at the new 2020 LiDAR data (topographic data showing subtle bumps and depressions) shows what appears to be the earthwork’s ditch at the enclosure’s north edge. Elsewhere, the ditch has been filled in by plowing or the construction of houses.

What’s even more interesting about this large enclosure, which actually is about 700 ft in diameter, is that it is located in the Hocking River Valley! Not many large earthwork sites have been recorded in this part of Ohio…but maybe we need to take a closer look? In fact, another earthwork enthusiast, David Lamp, has done just this and has spotted numerous earthworks that have been “lost” over the years. In 2017, David actually spotted this great circle (and many other enclosures) while scanning through old aerial photos. With both aerial and written documentation, this great circle is sure to be the real thing, and it will now be added to our maps of ancient Ohio earthwork sites.

04/04/2025

A few pics of Alexandra using the handheld magnetometer in the wooded area surveyed last month. SDMPS volunteers did a lot of clearing out the underbrush, picking up tree limbs and branches, etc., so the survey ropes could be properly placed.

A Pileated Woodpecker has been very busy by one of the mounds. We occasionally hear it at work. Not sure if this is for nesting or feeding.

03/04/2025

Two images of the results of the Snake Den Mounds Complex magnetic gradiometer survey funded by Heartland Earthworks Conservancy and an anonymous donor conducted on March 10-12th by Alexandra Flores of Ohio Valley Archaeology, Inc., with assistance of volunteers from the Snake Den Mounds Preservation Society (SDMPS). The survey shows that the outer enclosure continues south of the pipeline and appears to slightly go on to the adjacent property owner’s land to the south, though the barbed wire fence there is interfering with data collection.

There are a few other interesting anomalies (smaller black dots on the maps) to the southwest of the newly identified portion of the enclosure. This is not surprising. These likely represent pit features. We do not know if they are similar in age to the lines of pit features to the southeast of the mounds that we recently dated to about 700 – 500 BC, associated with the Adena Culture.

The more we know about Snake Den the more questions we have and desire to continue to learn more. HEC and SDMPS will begin drafting a National Register of Historic Places (NRHP) nomination for the site this summer. This is a somewhat lengthy process that often takes one to two years to complete before it is approved by the State Historic Preservation Office, the Governor-appointed Ohio Historic Site Preservation Advisory Board, and the National Park Service. Listing in the NRHP will not change ownership of the site or place restrictions on its use by SDMPS. It could open up additional paths for funds to do further research, etc., but its purpose is primarily honorific recognizing it as a place of historic significance by our local, state, and federal governments.

We are also concerned about a rumored effort by Columbia Gas to replace the 70-year-old pipeline. Given the significance of the site, they would have to stay within their existing easement to replace or relocate it. The Federal Energy Regulatory Commission may have jurisdiction over the matter and the State Historic Preservation Office may also be involved. However, the effects of President Trump's energy emergency Executive Order may complicate things. Stay tuned.

29/01/2025

We have new radiocarbon dates for the pit features between the outer enclosure and the rectangular enclosure to the southeast. They are somewhat similar in age to the radiocarbon date for the pit feature inside the outer enclosure, which dated to around 900 BC. The three new dates are a few centuries later/more recent than the previous date. Together, the four dates clearly indicate that the hilltop on which the Snake Den mound complex exists was the focus of activities, possibly ceremonial, centuries before the mounds and earthworks were built (we have no radiocarbon dates for these), in the early part of the Early Woodland period that is associated with the Adena Culture. These dates add to the many questions we have about the Snake Den complex, some of which we hope to address with the magnetometer survey of the woods south of the pipeline this spring. Stay tuned.

27/01/2025

We should soon be getting some new radiocarbon dates for linear pit features between the Snake Den Mounds and the rectangular earthwork in an adjacent field to the southeast (pic below). The only radiocarbon date we have on one of these pits dates its use to approximately 2900 years ago, maybe 1,000 years before we believe the mounds were erected!

We will also have additional magnetometer survey in the woods south of the pipeline done late this winter to see if the earthen ditch and embankment encloses the southern portion of the mound complex. Some exciting research results coming soon.